Optimization of Ohmic metal contacts for advanced GaAs-based CMOS device

摘要

Ohmic contact resistivity of a nongold Pd/Ge/Ti/Pt on highly doped molecular beam epitaxy grown n-GaAs and In_(0.2)Ga_(0.8)As/GaAs (～2 × 10~(18)cm~(-3)) has been investigated by varying Pd/Ge thicknesses and rapid thermal annealing (RTA) temperature/duration. An optimized Ohmic contact was obtained in the samples with Pd/Ge of 30 nm/30nm, using RTA at 300 ℃ for 10 s. Low Ohmic contact resistivity of 5.4 × 10~(-7) Ωcm~2 on n-In_(0.2)Ga_(0.8)As has been achieved. The mechanism of the contact resistivity reduction has been studied using the energy-dispersive x-ray spectroscopy depth profile.